A single mode infrared (IR) fiber laser using PbSe quantum dots as active medium is proposed according to the observed transmission electron microscope (TEM) images, absorption and emission spectra of the sodium-boron-aluminosilicate glass doped with PbSe quantum dots prepared before. The rate equations and lasing oscillation equation in a resonator are solved numerically. The optimal pumping wavelength, fiber length, doping concentration and reflectance of output mirror are obtained by using genetic algorithm. There is evidence that the quantum dots fiber laser (QDFL) possesses the saturated pumping power of 2 W, the maximum output of 1.36 W for 1676 nm lasing wavelength, and the pumping efficiency of 68%. Compared with the conventional fiber lasers that are doped with rare earth ions (e.g. Yb3+, Er3+), QDFL has characteristics of high pumping efficiency, low exciting threshold, adjustable doping density, and short saturated fiber length. The proposed QDFL can be developed into a novel multi-wavelength and wavelength-tunable laser due to lasing wavelength depending on the size of quantum dots.